JP2016223590A - Operating machine pressure oil energy regeneration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operating machine pressure oil energy regeneration apparatus capable of reliably securing a brake pressure even when an electrical failure occurs to a solenoid valve or the like and the solenoid valve or the like is erroneously opened.SOLUTION: An operating machine pressure oil energy regeneration apparatus comprises: a first hydraulic actuator 7; a second hydraulic actuator 6; and a first hydraulic pump 1 supplying a pressure oil to the first hydraulic actuator via a first oil passage 31, the operating machine pressure oil energy regeneration apparatus comprising: an upper control valve 5 which is connected to a discharge side of discharging the pressure oil from the second hydraulic actuator when a driven object of the second hydraulic actuator falls by a dead weight, and which can regulate a flow rate of the pressure oil discharged from the second hydraulic actuator; a communication oil passage 37 which connects the upper control valve to a hydraulic oil tank 30; a lower control valve 4 which is provided in the communication oil passage, and which can regulate a flow rate of the pressure oil discharged from the upper control valve to the hydraulic oil tank; and a regeneration oil passage 38 which has one end side connected to a branch point, between the upper control valve and the lower control valve, of the communication oil passage, and which has the other end side connected to the first oil passage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure oil energy recovery device for a work machine.

  For the purpose of providing a hydraulic control circuit for a work machine having a simple structure, excellent operability and energy efficiency, it is operated by a variable displacement pump and hydraulic oil supplied from the pump via a boom control valve. A regenerative circuit that branches from the oil passage between the boom cylinder discharge side and the flow rate adjustment valve that regulates the flow rate on the discharge side and communicates with the pump discharge side, and the pressure on the discharge side of the boom cylinder is higher than the pump discharge pressure. If the flow rate control valve is controlled to return to the pump discharge side through the regenerative circuit and perform regeneration, the regeneration side is set when regeneration is not performed. There is disclosed a hydraulic control circuit for a work machine including a controller that controls a pump so as to reduce a regenerative flow rate from a target pump discharge flow rate (for example, Patent Document 1). Irradiation).

JP 2008-025706 A

  According to the conventional technology described above, the pressure oil discharged from the bottom side oil chamber of the boom cylinder when the boom, which is the driven object of the boom cylinder, falls, can be regenerated to drive other actuators.

  However, in the above-described configuration of the prior art, when the solenoid valve of the flow control valve that returns the return oil from the boom cylinder to the pump discharge side is electrically broken and inadvertently opened, the bottom oil of the boom cylinder Pressure oil from the chamber is discharged through the solenoid valve, and the boom cylinder may fall at an unintended high speed.

  The present invention has been made on the basis of the above-mentioned matters, and its purpose is to ensure the brake pressure even when the electromagnetic valve or the like constituting the regenerator is erroneously opened due to an electrical failure. It is an object of the present invention to provide a pressure oil energy regeneration device for a work machine that can be used.

  In order to achieve the above object, the first invention provides a first hydraulic actuator, a second hydraulic actuator composed of a hydraulic cylinder different from the first hydraulic actuator, and a first hydraulic actuator. In a pressure oil energy recovery device for a work machine including a first hydraulic pump that supplies pressure oil through an oil passage and a hydraulic oil tank, when the driven object of the second hydraulic actuator falls by its own weight, An upper control valve connected to a discharge side from which pressure oil is discharged from the second hydraulic actuator and capable of adjusting a flow rate of the pressure oil discharged from the second hydraulic actuator; and the upper control valve and the hydraulic oil tank. A communication oil path to be connected, a lower control valve provided in the communication oil path, capable of adjusting a flow rate of pressure oil discharged from the upper control valve to the hydraulic oil tank, and in front of the communication oil path A regenerated oil passage having one end connected to a branch point between the upper control valve and the lower control valve and the other end connected to the first oil passage, and the pressure discharged from the second hydraulic actuator It is assumed that oil can be regenerated to the first actuator.

  Further, the second invention further comprises hydraulic pilot type operating means for operating the second hydraulic actuator in the first invention, and the upper control valve is generated by at least the hydraulic pilot type operating means. It operates based on the pilot pressure.

  Furthermore, a third invention is the first or second invention, wherein the first hydraulic actuator operating means for operating the first hydraulic actuator and the first actuator operating means are provided in the first oil passage. A first hydraulic actuator control valve operated by the first hydraulic control valve, wherein the first actuator control valve supplies pressure oil from the first hydraulic pump to the hydraulic oil tank when the first actuator operating means is not operated. It is a center bypass type that enables communication.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the first hydraulic actuator operating means for operating the first hydraulic actuator and the first actuator operating means operate, and the first actuator A first hydraulic actuator control valve that adjusts the direction and flow rate of pressure oil supplied from one hydraulic pump to the first hydraulic actuator, and is provided between the first hydraulic pump and the first hydraulic actuator control valve; A check valve for preventing backflow of pressure oil from the first hydraulic actuator to the first hydraulic pump; and the other end side of the regeneration oil passage is connected to the first hydraulic actuator control valve and the check valve. It is characterized by being connected between.

  Furthermore, a fifth invention is characterized in that, in any one of the first to fourth inventions, a regeneration valve capable of adjusting a flow rate of the pressure oil to be regenerated is provided in the regeneration oil passage.

  According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the switching valve capable of switching the flow destination of the pressure oil discharged from the upper control valve to the regenerated oil passage or the lower control valve. Is provided in place of the regeneration valve.

  Furthermore, a seventh invention is characterized in that, in the sixth invention, the switching valve is provided with a variable throttle in the internal oil passage on the regeneration oil passage side.

  The eighth invention is characterized in that, in the sixth invention, the switching valve is provided with a variable throttle in the internal oil passage on the lower control valve side.

  Further, according to a ninth invention, in any one of the second to eighth inventions, a second hydraulic pump that supplies pressure oil to the second hydraulic actuator via a second oil passage, and the first hydraulic pump. And a third oil passage for supplying the second hydraulic actuator to the second hydraulic actuator, wherein the upper control valve is provided in the second oil passage, and the lower control valve is provided in the third oil passage. When the driven object of the second hydraulic actuator is operated in the upward direction by the hydraulic pilot type operating means, the pressure oil from the first hydraulic pump passes through the lower control valve and the second hydraulic pressure Pressure oil from a pump is supplied to each of the second hydraulic actuators via the upper control valve.

  According to the present invention, even when an electrical failure occurs in an electromagnetic valve or the like that constitutes the regenerator and it is erroneously opened, the brake pressure can be reliably ensured. As a result, it is possible to provide a pressure oil energy regeneration device for a work machine that is safe and highly reliable.

It is the schematic of the control system which shows 1st Embodiment of the pressure oil energy reproduction | regeneration apparatus of the working machine of this invention. It is a flowchart figure which shows the processing content of the controller which comprises 1st Embodiment of the pressure oil energy reproduction | regeneration apparatus of the working machine of this invention. It is a characteristic view which shows an example of the opening area characteristic with respect to the pilot pressure of the upper control valve which comprises 1st Embodiment of the pressure oil energy reproduction | regeneration apparatus of the working machine of this invention. It is the schematic of the control system which shows 2nd Embodiment of the pressure oil energy reproduction | regeneration apparatus of the working machine of this invention. It is the schematic of the control system which shows 3rd Embodiment of the pressure oil energy reproduction | regeneration apparatus of the working machine of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a pressure oil energy regenerating apparatus for a working machine according to the present invention will be described with reference to the drawings. Note that a hydraulic excavator will be described as an example of the work machine.

  FIG. 1 is a schematic diagram of a control system showing a first embodiment of a pressure oil energy regenerating apparatus for a work machine according to the present invention. In FIG. 1, 1 and 2 are variable displacement type first and second hydraulic pumps driven by an engine (not shown), 3 is an arm control valve, 4 is a boom lower control valve, and 5 is a boom upper control. Valve, 6 is a boom cylinder as a second hydraulic actuator, 7 is an arm cylinder as a first hydraulic actuator, 8 is a regeneration valve, 9 is a boom operating device, 10 is an arm operating device, and 20 is a controller (control means). , 30 indicates a hydraulic oil tank. The first hydraulic pump 1 and the second hydraulic pump 2 have, for example, a swash plate as a variable displacement mechanism, and the displacement (displacement) of each pump is adjusted by adjusting the tilt angle of the swash plate with the capacity control devices 1a and 2a. Volume) is changed, and the discharge flow rate of the pressure oil is controlled.

  An arm control valve 3 and a boom lower control valve 4 are provided from the upstream side in the first main pipeline 31 that supplies pressure oil discharged from the first hydraulic pump 1 to the actuators of the boom cylinder 6 and the arm cylinder 7. They are arranged in series. The boom upper control valve 5 is disposed in the second main pipeline 32 that supplies pressure oil discharged from the second hydraulic pump 2 to the boom cylinder 6.

  The arm control valve 3 is a three-position six-port switching control valve, and the control valve position is switched by the pilot pressure supplied to both pilot operation sections 3X and 3Y, so that the opening area of the hydraulic oil flow path To change. Thus, the arm cylinder 7 is driven by controlling the direction and flow rate of hydraulic oil supplied from the first hydraulic pump 1 to the arm cylinder 7. The arm control valve 3 includes an inlet port 3c to which pressure oil from the first hydraulic pump 1 is supplied, an outlet port 3d that communicates with the hydraulic oil tank 30, and a center port 3T that communicates when in the neutral position. Further, it has a connection port 3a, 3b connected to the arm cylinder 7 side, and is a center bypass type that communicates the pressure oil from the first hydraulic pump 1 to the hydraulic oil tank 30 when in the neutral position. Note that a check valve 14 that permits only outflow from the first hydraulic pump 1 is provided in a pipe connecting the first main pipeline 31 and the inlet port 3c.

  The boom lower control valve 4 and the boom upper control valve 5 are three-position 7-port switching control valves, which are controlled by the pilot pressure supplied to both pilot operation sections 4X, 5X, 4Y, and 5Y. The position is switched to change the opening area of the hydraulic oil flow path. Specifically, when pilot pressure is supplied to the pilot operating units 4Y and 5Y, the lower boom control valve 4 moves to the left, and the upper boom control valve 5 moves to the right, respectively, at the A position. Switched. Conversely, when pilot pressure is supplied to the pilot operating sections 4X and 5X, the lower boom control valve 4 moves to the right and the boom upper control valve 5 moves to the left, and each is switched to the B position. . By these operations, the boom cylinder 6 is driven by controlling the direction and flow rate of hydraulic oil supplied from the first hydraulic pump 1 and / or the second hydraulic pump 2 to the boom cylinder 6.

  Further, the boom upper control valve 5 is connected to an inlet port 5c to which pressure oil from the second hydraulic pump 2 is supplied, to an outlet port 5d that communicates with the hydraulic oil tank 30, and to a communication conduit 37 that will be described later. It has a port 5e, a center port 5T that communicates when in the neutral position, and connection ports 5a and 5b that are connected to the boom cylinder 6 side. When in the neutral position, pressure oil from the second hydraulic pump 2 is supplied. The center bypass type communicates with the hydraulic oil tank 30. A check valve 12 that permits only outflow from the second hydraulic pump 2 is provided in a pipe connecting the second main pipeline 32 and the inlet port 5c. In addition, a throttle is provided in the internal oil passage that communicates from the connection port 5a to the connection port 5e at the position A of the boom upper control valve 5.

  The lower boom control valve 4 is connected to an inlet port 4c to which pressure oil from the first hydraulic pump 1 is supplied, to an outlet port 4d communicating with the hydraulic oil tank 30, and to a communication conduit 37 described later. It has a port 4e, a center port 4T that communicates at the neutral position, and connection ports 4a and 4b that are connected to the boom cylinder 6 side. When in the neutral position, pressure oil from the first hydraulic pump 1 is supplied. The center bypass type communicates with the hydraulic oil tank 30. Note that a check valve 13 that permits only outflow from the first hydraulic pump 1 is provided in a pipe connecting the first main pipeline 31 and the inlet port 4c. In addition, a throttle is provided in the internal oil passage that communicates from the connection port 4e to the connection port 4a at the A position of the boom lower control valve 4. Furthermore, one end side of the communication conduit 37 is connected to the connection port 4 e, and the other end side of the communication conduit 37 is connected to the connection port 5 e of the boom upper control valve 5.

  The boom cylinder 6 includes a cylinder and a piston rod, and the cylinder includes a bottom-side oil chamber 6a and a rod-side oil chamber 6b. One end of the first conduit 33 is connected to the bottom oil chamber 6a, and the other end of the first conduit 33 is connected to the connection port 4a of the boom lower control valve 4 and the boom upper control valve 5. To the connection port 5a. One end of the second pipe 34 is connected to the rod-side oil chamber 6b, and the other end of the second pipe 34 is connected to the connection port 4b of the boom lower control valve 4 and the boom upper control valve 5. To the connection port 5b. The first pipe 33 is provided with a pressure sensor 16 that detects the pressure in the bottom oil chamber 6a of the boom cylinder 6. The pressure signal Pb of the boom cylinder bottom side oil chamber 6 a detected by the pressure sensor 16 is input to the controller 20.

  The arm cylinder 7 includes a cylinder and a piston rod, and the cylinder includes a bottom-side oil chamber 7a and a rod-side oil chamber 7b. One end side of the third pipeline 35 is connected to the bottom side oil chamber 7 a, and the other end side of the third pipeline 35 is connected to the connection port 3 a of the arm control valve 3. One end side of the fourth conduit 36 is connected to the rod-side oil chamber 7 b, and the other end of the fourth conduit 36 is connected to the connection port 3 b of the arm control valve 3. The fourth pipe 36 is provided with a pressure sensor 17 that detects the pressure in the rod-side oil chamber 7b of the arm cylinder 6. The pressure signal Pr of the arm cylinder rod side oil chamber 7 b detected by the pressure sensor 17 is input to the controller 20.

  The communication pipe 37 is for discharging the return oil from the bottom side oil chamber 6 a of the boom cylinder 6 from the boom upper control valve 5 to the hydraulic oil tank 30 via the boom lower control valve 4. A branch portion to which one end side of the regeneration conduit 38 is connected is provided at an intermediate portion of the communication conduit 37. The other end side of the regeneration pipeline 38 is connected to the first main pipeline 31 via a check valve 15 that permits only outflow from the regeneration pipeline 38.

  In addition, the other end side of the regeneration pipeline 38 is connected to the inlet port 3c of the arm control valve 3 from the first hydraulic pump 1 of the first main pipeline 31 as compared with the check valve 14 provided in the pipe. Connected to the site. In addition, the regeneration pipe 38 is provided with a regeneration valve 8 that is a 2-port 2-position electromagnetic switching valve. The regenerative valve 8 includes an operating portion that receives a command from the controller 20 and a spring portion, and is controlled to be in the open position by the shut-off position and the command signal when there is no command signal from the controller 20. .

  The boom operation device 9 includes an operation lever and a pilot valve 9a, and generates a pilot pressure corresponding to the operation amount of the tilt operation of the operation lever. From the boom operation device 9, a pilot line indicated by a broken line is connected to the operation units 4X, 4Y, 5X, and 5Y of the boom lower control valve 4 and the boom upper control valve 5. When the operating lever is operated to the boom raising side, the generated boom raising pilot pressure Pu is supplied to the operating portion 4X of the boom lower control valve 4 and the operating portion 5X of the boom upper control valve 5, and the boom lower control valve 4 is supplied. The boom upper control valve 5 performs switching control according to the pilot pressure. Similarly, when the operation lever is operated to the boom lowering side, the generated boom lowering pilot pressure Pd is supplied to the operation unit 4Y of the boom lower control valve 4 and the operation unit 5Y of the boom upper control valve 5, and the boom lower part The control valve 4 and the boom upper control valve 5 perform switching control according to the pilot pressure.

  The arm operating device 10 includes an operating lever and a pilot valve 10a, and generates a pilot pressure corresponding to the operation amount of the tilting operation of the operating lever. From the arm operation device 10, pilot lines indicated by broken lines are connected to the operation units 3 </ b> X and 3 </ b> Y of the arm control valve 3. When the operation lever is operated to the cloud side, the generated arm cloud pilot pressure Pi is supplied to the operation unit 3X of the arm control valve 3, and the arm control valve 3 performs switching control according to the pilot pressure. Similarly, when the operation lever is operated to the dump side, the generated arm dump pilot pressure Po is supplied to the operation unit 3Y of the arm control valve 3, and the arm control valve 3 performs switching control according to the pilot pressure. Do.

  The boom lowering pilot line and the arm dump pilot line are provided with a pressure sensor 18 for detecting the boom lowering pilot pressure Pd and a pressure sensor 19 for detecting the arm dump pilot pressure Po. The pressure signals detected by these pressure sensors 18 and 19 are input to the controller 20.

  The controller 20 inputs the boom cylinder bottom side oil chamber pressure Pb, the arm cylinder rod side oil chamber pressure Pr, the boom lowering pilot pressure Pd, and the arm dump pilot pressure Po detected by the pressure sensors 16 to 19, Based on these signals, a control command to the regeneration valve 8 is output.

  Next, the operation of the above-described first embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention will be described. First, the boom lowering operation by the operator will be described.

  In FIG. 1, when the boom lowering operation is performed by the operation lever of the boom operating device 9, the boom lowering pilot pressure Pd generated from the pilot valve 9 a is the operating portion 4 </ b> Y of the boom lower control valve 4 and the boom upper control valve. 5 operation unit 5Y. As a result, the lower boom control valve 4 moves to the left and the upper boom control valve 5 moves to the right, and each is switched to the A position.

  As a result, the pressure oil from the first hydraulic pump 1 passes from the inlet port 4c of the lower boom control valve 4 through the connection port 4b to the rod side oil chamber 6b of the boom cylinder 6 through the second pipe 34. Supplied. Further, the pressure oil from the second hydraulic pump 2 is supplied from the inlet port 5c of the boom upper control valve 5 to the rod side oil chamber 6b of the boom cylinder 6 via the connection port 5b and the second pipe 34. Is done.

  On the other hand, the return oil discharged from the bottom oil chamber 6a of the boom cylinder 6 flows into the communication pipe 37 via the first pipe 33 and the connection port 5a of the boom upper control valve 5 via the connection port 5e. To do. The pressure oil that has flowed in is discharged from the connection port 4e of the lower control valve 4 for the boom to the hydraulic oil tank 30 via the throttle provided inside and the outlet port 4d. Thus, the pressure oil from the first hydraulic pump 1 and the second hydraulic pump 2 flows into the rod side oil chamber 6b of the boom cylinder 6, and the pressure oil in the bottom side oil chamber 6a The oil is discharged to the hydraulic oil tank 30 through the control valve 5 and the lower boom control valve 4. As a result, the piston rod of the boom cylinder 6 is shortened, and the boom operates in the lowering direction.

Next, an arm dump operation by the operator will be described.
In FIG. 1, when the arm dump operation is performed by the operation lever of the arm operation device 10, the arm dump pilot pressure Po generated from the pilot valve 10 a is supplied to the operation unit 3 </ b> Y of the arm control valve 3. As a result, the arm control valve 4 moves to the left and is switched to the A position.

  As a result, the pressure oil from the first hydraulic pump 1 is supplied from the inlet port 3 c of the arm control valve 3 to the rod side oil chamber 7 b of the arm cylinder 7 via the connection port 3 b and the fourth pipe 36. Is done.

  On the other hand, the return oil discharged from the bottom side oil chamber 7a of the arm cylinder 7 is discharged to the hydraulic oil tank 30 via the third pipe 35 and the connection port 3a of the arm control valve 3 through the outlet port 3d. Is done. Thus, the pressure oil from the first hydraulic pump 1 flows into the rod side oil chamber 7 b of the arm cylinder 7, and the pressure oil in the bottom side oil chamber 7 a operates through the arm control valve 3. It is discharged to the oil tank 30. As a result, the piston rod of the arm cylinder 7 contracts and the arm moves in the dumping direction.

  Next, the operation of simultaneously performing the boom lowering operation and the arm dumping operation by the operator and regenerating the return oil from the boom cylinder 6 to the arm cylinder 7 will be described. When the return oil of the boom cylinder 6 is regenerated to the arm cylinder 7, the regeneration valve 8 is controlled by the controller 20 in addition to the boom lowering operation and the arm dumping operation described above. Since the operations of the first hydraulic pump 1, the second hydraulic pump 2, the arm control valve 3, the boom lower control valve 4, and the boom upper control valve 5 are the same as described above, detailed description thereof is omitted.

  When the boom lowering operation is performed by the operation lever of the boom operating device 9, the boom lowering pilot pressure Pd generated from the pilot valve 9 a is detected by the boom lowering pilot pressure sensor 18 and input to the controller 20. Further, when the arm dump operation is performed by the operation lever of the arm operation device 10, the arm dump pilot pressure Po generated from the pilot valve 10 a is detected by the arm dump pilot pressure sensor 19 and input to the controller 20.

  Further, the pressure Pb in the bottom side oil chamber 6 a of the boom cylinder 6 is detected by the boom cylinder bottom side oil chamber pressure sensor 16 and input to the controller 20. The pressure Pr in the rod side oil chamber 7 b of the arm cylinder 7 is detected by the arm cylinder rod side oil chamber pressure sensor 17 and input to the controller 20.

  The controller 20 calculates a command signal based on each input signal, and outputs the command signal to the regeneration valve 8 for switching. When the regeneration valve 8 is switched from the shut-off position to the open operation position, from the bottom side oil chamber 6a of the boom cylinder 6 that has flowed into the communication conduit 37 from the connection port 5a of the boom upper control valve 5 via the connection port 5e. The discharged return oil flows into the regeneration pipe line 38 through the regeneration valve 8. The return oil that has flowed into the regeneration line 38 flows into the first main line 31 that is the discharge side of the first hydraulic pump 1 via the check valve 15. As a result, the return oil from the boom cylinder 6 is regenerated to the arm cylinder 7 via the arm control valve 3, and the driving speed of the piston rod of the arm cylinder 7 can be increased.

  Further, it is possible to save energy by controlling the displacement control device 1a of the first hydraulic pump 1 to suppress the discharge flow rate of the first hydraulic pump 1 and suppressing the output of the first hydraulic pump 1.

  Next, processing contents of the controller 20 will be described with reference to FIG. FIG. 2 is a flowchart showing the processing contents of the controller constituting the first embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention.

  First, as a start state, for example, an operator turns on a key switch (not shown) of a hydraulic excavator. The controller 20 takes in the pressure signals (the boom cylinder bottom side oil chamber pressure Pb, the arm cylinder rod side oil chamber pressure Pr, the boom lowering pilot pressure Pd, and the arm dump pilot pressure Po) detected by the pressure sensors 16 to 19 (steps). S1).

  Next, the controller 20 determines whether or not the detected boom lowering pilot pressure Pd is higher than a predetermined pilot set pressure 1 (step S2). Specifically, it is determined whether the operation amount of the boom operation device 9 is equal to or greater than a predetermined operation amount. When the boom lowering pilot pressure Pd is higher than the pilot set pressure 1 (when the operation amount is equal to or larger than the predetermined operation amount), the process proceeds to (Step S3), and otherwise the process proceeds to (Step S6).

  The controller 20 determines whether or not the detected arm dump pilot pressure Po is higher than a predetermined pilot set pressure 2 (step S3). Specifically, it is determined whether or not the operation amount of the arm operation device 10 is equal to or greater than a predetermined operation amount. When the arm dump pilot pressure Po is higher than the pilot set pressure 2 (when the operation amount is equal to or greater than the predetermined operation amount), the process proceeds to (Step S4), and otherwise the process proceeds to (Step S6).

  The controller 20 determines whether or not the detected boom cylinder bottom side oil chamber pressure Pb is higher than the detected arm cylinder rod side oil chamber pressure Pr (step S4). Specifically, it is determined whether or not regeneration from the boom cylinder 6 to the arm cylinder 7 is possible. If the boom cylinder bottom side oil chamber pressure Pb is higher than the arm cylinder rod side oil chamber pressure Pr, the process proceeds to (Step S5), and otherwise the process proceeds to (Step S6).

  The controller 20 outputs an opening command to the regeneration valve 8 (step S5). Specifically, the boom operating device 9 is operated to lower the boom exceeding the predetermined amount, the arm operating device 10 is operated to perform the arm dump operation exceeding the predetermined amount, and the bottom oil chamber pressure Pb of the boom cylinder is set to the arm cylinder rod. If it is determined that the pressure is higher than the side oil chamber pressure Pr, a command signal for opening the regeneration valve 8 is output. As a result, the regeneration valve 8 opens, and the return oil from the bottom oil chamber 6a of the boom cylinder 6 that flows into the communication conduit 37 flows into the regeneration conduit 38 via the regeneration valve 8, and the first It flows into the first main pipeline 31 that is the discharge side of the hydraulic pump 1. As a result, the return oil from the boom cylinder 6 is regenerated to the arm cylinder 7 via the arm control valve 3. After executing the process of (Step S5), the process returns via the return to (Step S1) and starts again.

  The controller 20 outputs a close command to the regeneration valve 8 (step S6). Specifically, when it is determined that any of the conditions of (Step S2), (Step S3), and (Step S4) is not satisfied, a close command is output to the regeneration valve 8, and the regeneration valve 8 is not operated. In the present embodiment, this is realized by not outputting an open command signal. After executing the process of (Step S6), the process returns to (Step S1) via a return and starts the process again.

  Next, the operation in the case where an electrical failure occurs in the regenerative valve or the like and the opening operation is erroneously described will be described with reference to FIGS. FIG. 3 is a characteristic diagram showing an example of the opening area characteristic with respect to the pilot pressure of the upper control valve constituting the first embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention.

  First, a case where the boom operation device 9 is not operated will be described. As shown in FIG. 1, when the bottom side oil chamber 6a of the boom cylinder 6 is the most upstream of the return oil, the boom upper control valve 5 is disposed upstream of the regeneration line 38 where the regeneration valve 8 is disposed. ing. When the boom operation device 9 is not operated, the boom lowering pilot pressure Pd is not generated from the pilot valve 9a, and therefore the boom upper control valve 5 is closed. For this reason, even if the regeneration valve 8 arranged on the downstream side is erroneously opened, the state of the return oil from the bottom side oil chamber 6a of the boom cylinder 6 does not change, and the piston rod of the boo cylinder 6 is not intended. No fall occurs.

  Next, a case where the boom operation device 9 is finely operated will be described. As described above, a throttle is provided in the internal oil passage that communicates from the connection port 5a to the connection port 5e at the position A of the boom upper control valve 5. With this restriction, the opening area of the boom upper control valve 5 is appropriately restricted according to the boom lowering pilot pressure Pd as shown in FIG. For this reason, even if the boom upper control valve 5 is opened by fine operation of the boom operation device 9 and the regeneration valve 8 is opened by mistake, the speed is adjusted by the boom upper control valve 5 and the boom cylinder 6 The rapid drop speed increase of the piston rod can be suppressed.

  From the characteristics shown in FIG. 3, when the boom lowering pilot pressure Pd corresponds to fine operation, the boom upper control valve 5 is almost closed. As the boom lowering pilot pressure Pd increases, the opening area of the boom upper control valve 5 gradually increases. Thus, regardless of the state of the operation amount of the boom lowering operation, the brake pressure can be secured and safety can be achieved.

  The energy of the return oil from the bottom side oil chamber 6a of the boom cylinder 6 during the boom lowering operation is sufficiently larger than the energy input from the first hydraulic pump 1 to the arm cylinder 7 during the arm dump operation. For this reason, even if the above-mentioned throttle is provided in the internal oil passage of the boom upper control valve 5 and the flow rate of the return oil from the bottom oil chamber 6a of the boom cylinder 6 is throttled to some extent, the regeneration used for arm dumping. Safety and energy efficiency can be improved with almost no effect on the quantity.

  By the way, a general hydraulic excavator generally employs a configuration in which pressure oil is supplied from two or more hydraulic pumps to the boom cylinder when the boom cylinder is raised. In this case, as many control spools as the number of hydraulic pumps for switching and supplying the hydraulic oil of the hydraulic pump are required. On the other hand, when performing the lowering operation of the boom cylinder, only one control spool for adjusting the pressure oil discharged from the bottom side oil chamber of the boom cylinder to the hydraulic oil tank 30 is often arranged. For this reason, an excess may occur in the control spool during the boom lowering operation.

  In the first embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention, two control spools necessary for the boom raising operation are also used for the boom lowering operation, one of which is for the boom. The upper control valve 4 uses an internal oil passage throttle for safety, and the other one uses a boom lower control valve 5 for adjusting the internal oil passage for speed adjustment. As a result, it is possible to share the control spool necessary for boom raising operation without adding an extra control valve. Thus, it is possible to provide a pressure oil energy regeneration device for a work machine that can ensure a braking force reliably.

  According to the first embodiment of the pressure oil energy regeneration device for a work machine of the present invention described above, even if an electrical failure occurs in the regeneration valve 8 or the like constituting the regeneration device and the operation is erroneously opened. The brake pressure can be ensured reliably. As a result, it is possible to provide a pressure oil energy regeneration device for a work machine that is safe and highly reliable.

  According to the first embodiment of the pressure oil energy regenerating apparatus for a work machine of the present invention described above, return oil from the bottom oil chamber 6a of the boom cylinder 6 during the boom lowering operation is supplied to the arm cylinder 7 and the like. When the hydraulic actuator is used for driving, the boom upper control valve 5 adjusts the return oil upstream of the regenerator so that safety can be ensured regardless of the amount of boom lowering operation. . As a result, safety and energy saving efficiency can be improved. Furthermore, since the boom raising control spool and the boom lowering control spool are shared, it is possible to provide a pressure oil energy regeneration device for a work machine with a simple configuration without adding an extra valve.

Hereinafter, a second embodiment of a pressure oil energy regenerating apparatus for a working machine according to the present invention will be described with reference to the drawings. FIG. 4 is a schematic diagram of a control system showing a second embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention.
In the second embodiment of the pressure oil energy regenerating apparatus for work machine according to the present invention, the general system of the regenerating apparatus is the same as that of the first embodiment, but the regenerating valve 8 is replaced with a switching electromagnetic valve 21. This is different from the first embodiment. Specifically, as shown in FIG. 4, the communication valve 37 is provided with a switching valve 21 that is an electromagnetic switching valve at a 3-port 2-position. The other end of the communication line 37 connected at one end to the boom upper control valve 5 is connected to the inlet port of the switching valve 21, and the boom lower control valve 4 is connected to the first outlet port of the switching valve 21. The other end side of the communication pipe line 37 to which one end side is connected is connected. One end side of the regeneration pipe line 38 is connected to the second outlet port of the switching valve 21, and the other end side of the regeneration pipe line 38 is passed through a check valve 15 that permits only outflow from the regeneration pipe line 38. And connected to the first main pipeline 31.

  The switching valve 21 includes an operating portion that receives a command from the controller 20 and a spring portion. When there is no command signal from the controller 20, the pressure oil in the communication line 37 is sent to the lower control valve 4 for the boom. The flow path of the return oil from the boom cylinder 6 is switched by switching to one of the positions where the pressure oil in the communication pipe 37 is sent to the regeneration pipe 38 by a command signal. The two internal oil passages of the switching valve 21 are provided with variable throttles 21a and 21b that can adjust the opening area of the oil passage on the boom lower control valve 4 side and the opening area of the oil passage on the regeneration pipe side 38, respectively. Yes.

  In the configuration of the regeneration valve 8 in the first embodiment, the return oil discharged from the bottom oil chamber 6a of the boom cylinder 6 and flowing into the communication conduit 37 is sent to the boom lower control valve 4 and the regeneration conduit 38. If the regeneration flow rate is increased too much because the flow is diverted, the flow rate of the return oil discharged from the boom cylinder 6 increases, and the dropping speed of the piston rod of the boom cylinder 6 may become too fast.

  On the other hand, in the configuration of the switching valve 21 in the present embodiment, all the return oil discharged from the boom cylinder 6 is reduced by reducing or reducing the flow rate of the return oil flowing into the lower boom control valve 4. Can be played. This can further improve the energy saving effect.

  Furthermore, even when an electrical failure occurs during regeneration and the position is changed to the position where the boom lower control valve 4 is accidentally switched, all of the return oil discharged from the boom upper control valve 5 is removed. 4, the normal boom lowering operation is performed, the speed of the piston rod of the boom cylinder 6 does not change suddenly, and safety can be ensured.

  According to the second embodiment of the pressure oil energy regenerating apparatus for a working machine of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

  In addition, according to the second embodiment of the pressure oil energy regenerating apparatus for work machine of the present invention described above, since the switching valve 21 is used, the energy saving effect can be further improved, and the regeneration is performed due to an electrical failure. Even if the switching valve is switched unexpectedly sometimes, the speed of the piston rod of the boom cylinder 6 does not change suddenly, and safety can be ensured.

  Further, according to the second embodiment of the pressure oil energy regenerating apparatus for work machine of the present invention described above, the variable throttles 21a and 21b are provided in the two internal oil passages of the switching valve 21, respectively. The switching shock can be reduced, and a sudden change in the speed of the piston rod of the boom cylinder 6 can be suppressed. As a result, operability and safety can be improved.

  In the present embodiment, the case where the variable throttle is provided in both of the two internal oil passages of the switching valve 21 has been described as an example, but the present invention is not limited to this. A variable throttle may be provided in either the oil passage on the regeneration conduit side 38 or the oil passage on the boom lower control valve 4 side.

Hereinafter, a third embodiment of a pressure oil energy regenerating apparatus for a working machine according to the present invention will be described with reference to the drawings. FIG. 5 is a schematic diagram of a control system showing a third embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention.
In the third embodiment of the pressure oil energy regenerating apparatus for a work machine according to the present invention, the schematic system of the regenerating apparatus is the same as that of the first embodiment, but the first side on the other end side of the regenerating line 38 is the same. The connection point with the main pipeline 31 is different from that of the first embodiment. Specifically, as shown in FIG. 5, the other end side of the regeneration pipe line 38 is connected to a pipe between the inlet port 3 c of the arm control valve 3 and the check valve 14.

  Since the destination of the pressure oil from the first hydraulic pump 1 and the return oil from the regeneration pipe 38 is disposed between the check valve 14 and the arm control valve 3, the operation lever of the arm operation device 10 is operated. If not, no pilot pressure is generated from the pilot valve 10a, and the arm control valve 3 is not switched. Therefore, an electrical failure occurs in the regenerative valve 8 and the like constituting the regenerator, and the open operation is erroneously performed. Even in this case, the return oil is not discharged to the hydraulic oil tank 30. Therefore, it is possible to prevent the occurrence of dropping of the piston rod of the boom cylinder 6 unintended by the operator.

  According to the third embodiment of the pressure oil energy regenerating apparatus for a work machine of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

Further, according to the third embodiment of the above-described pressure oil energy regeneration device for a work machine according to the present invention, a check valve is used to check the junction of the pressure oil from the first hydraulic pump 1 and the return oil from the regeneration pipeline 38. 14 and the arm control valve 3, an electrical failure occurs in the regenerative valve 8 or the like when the operating lever of the arm operating device 10 is not operated and the arm control valve 3 cannot be switched. Even if the opening operation is erroneously performed, the return oil is not discharged into the hydraulic oil tank 30, and the unintentional dropping of the piston rod of the boom cylinder 6 can be prevented. As a result, the safety can be further improved. The present invention is not limited to the first to third embodiments described above, and includes various modifications. The above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. For example, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace another configuration for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 1st hydraulic pump 2 2nd hydraulic pump 3 Arm control valve 4 Boom lower control valve 5 Boom upper control valve 6 Boom cylinder (2nd hydraulic actuator)
6a Bottom side oil chamber 6b Rod side oil chamber 7 Arm cylinder (first hydraulic actuator)
7a Bottom side oil chamber 7b Rod side oil chamber 8 Regenerative valve 9 Boom operating device 10 Arm operating device 14 Arm control valve check valve (check valve)
15 Regeneration line check valve 16 Boom cylinder bottom side oil chamber pressure sensor 17 Arm cylinder rod side oil chamber pressure sensor 18 Boom lowering pilot pressure sensor 19 Arm dump pilot pressure sensor 20 Controller 21 Switching valve 21a Variable throttle 21b Variable throttle 30 Operation Oil tank 31 1st main pipe line (1st oil path)
32 Second main pipeline (second oil passage)
33 First pipeline (third oil passage)
34 Second pipe 37 Communication pipe (communication oil pipe)
38 Regeneration pipeline (recycled oil passage)

Claims (10)

A first hydraulic actuator, a second hydraulic actuator composed of a hydraulic cylinder different from the first hydraulic actuator, and a first hydraulic pump for supplying pressure oil to the first hydraulic actuator via a first oil path In the pressure oil energy regeneration device for a work machine equipped with a hydraulic oil tank,
When the driven object of the second hydraulic actuator falls by its own weight, it is connected to the discharge side from which the pressure oil is discharged from the second hydraulic actuator, and the flow rate of the pressure oil discharged from the second hydraulic actuator can be adjusted. An upper control valve,
A communication oil path connecting the upper control valve and the hydraulic oil tank;
A lower control valve that is provided in the communication oil passage and is capable of adjusting a flow rate of pressure oil discharged from the upper control valve to the hydraulic oil tank;
One end side is connected to a branch point between the upper control valve and the lower control valve of the communication oil path, and the other end side is connected to the first oil path.
The pressure oil energy regeneration device for a work machine, wherein the pressure oil discharged from the second hydraulic actuator can be regenerated to the first actuator. In the pressure oil energy reproduction | regeneration apparatus of the working machine of Claim 1,
A hydraulic pilot operating means for operating the second hydraulic actuator;
The upper control valve operates based on at least a pilot pressure generated by the hydraulic pilot type operating means. In the pressure oil energy reproduction | regeneration apparatus of the working machine of Claim 1 or 2,
A first hydraulic actuator operating means for operating the first hydraulic actuator; and a first hydraulic actuator control valve provided in the first oil passage and operated by the first actuator operating means,
The first actuator control valve is of a center bypass type that allows pressure oil from the first hydraulic pump to communicate with the hydraulic oil tank when the first actuator operating means is not operated. Pressure oil energy regenerator for working machines. In the pressure oil energy reproduction | regeneration apparatus of the working machine of any one of Claims 1 thru | or 3,
A first hydraulic actuator operating means for operating the first hydraulic actuator; and a direction and flow rate of pressure oil which is operated by the first actuator operating means and is supplied from the first hydraulic pump to the first hydraulic actuator. A first hydraulic actuator control valve to be adjusted;
A check valve provided between the first hydraulic pump and the first hydraulic actuator control valve to prevent backflow of pressure oil from the first hydraulic actuator to the first hydraulic pump;
A pressure oil energy regeneration device for a working machine, wherein the other end of the regeneration oil passage is connected between the first hydraulic actuator control valve and the check valve. In the pressure oil energy reproduction | regeneration apparatus of the working machine of any one of Claims 1 thru | or 4,
A pressure oil energy regeneration device for a working machine, wherein a regeneration valve capable of adjusting a flow rate of the pressure oil to be regenerated is provided in the regeneration oil path. In the pressure oil energy reproduction | regeneration apparatus of the working machine of any one of Claims 1 thru | or 4,
A pressure oil for a working machine, characterized in that a switching valve capable of switching the flow destination of the pressure oil discharged from the upper control valve to the regeneration oil path or the lower control valve is provided in place of the regeneration valve. Energy regeneration device. In the pressure oil energy reproduction | regeneration apparatus of the working machine of Claim 6,
The pressure oil energy regeneration device for a work machine, wherein the switching valve is provided with a variable throttle in an internal oil passage on the regeneration oil passage side. In the pressure oil energy reproduction | regeneration apparatus of the working machine of Claim 6,
The pressure oil energy regeneration device for a work machine, wherein the switching valve is provided with a variable throttle in an internal oil passage on the lower control valve side. In the pressure oil energy reproduction | regeneration apparatus of the working machine of any one of Claim 2 thru | or 8,
A second hydraulic pump for supplying pressure oil to the second hydraulic actuator via a second oil path; and a third oil path for supplying pressure oil from the first hydraulic pump to the second hydraulic actuator. ,
The upper control valve is provided in the second oil passage,
The lower control valve is provided in the third oil passage,
When the driven object of the second hydraulic actuator is operated in the upward direction by the hydraulic pilot type operating means, the pressure oil from the first hydraulic pump passes through the lower control valve and the second hydraulic pump. The pressure oil from the working machine is supplied to the second hydraulic actuator via the upper control valve, respectively. In the pressure oil energy reproduction | regeneration apparatus of the working machine of any one of Claim 2 thru | or 8,
A second hydraulic pump for supplying pressure oil to the second hydraulic actuator via a second oil path; and a third oil path for supplying pressure oil from the first hydraulic pump to the second hydraulic actuator. ,
The upper control valve is provided in the third oil passage,
The lower control valve is provided in the second oil passage,
When the driven object of the second hydraulic actuator is operated in the upward direction by the hydraulic pilot type operating means, the pressure oil from the first hydraulic pump passes through the upper control valve and the second hydraulic pump. The pressure oil from the working machine is supplied to the second hydraulic actuator via the lower control valve, respectively.

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